THEORETICAL BACKGROUND OF POSTURAL...

THEORETICAL BACKGROUND OF POSTURAL CONTROL

Postural Control – Role In The Human Movement

대전 보람병원

이기훈

2015 한국보바스 소아학술대회

Key word

• Postural control : 중력에 대응공갂에서 자세를 유지어떤 동작을 수행이 가능하도록 하는 배경보행이나 manual skill 발달의 기초

• 중추신경계- 공갂에서의 신체의 위치와 움직임에 대한 정보를 제

공하는 많은 감각 정보를 받아들임.- 통합- 여러 조절단계- 몸통 및 사지의 귺육에 적절한 수축과 이완 유도

Key word

• Vestibular system

• Muscles which locate around the neck are most important, which is the basis for the postural control of human movement

• The top is the head which is the keystone of the central line

Gravity

Human Movement

• The same way to move against gravity

• Normal postural control mechanism

• All of these are all generated postural control, without conscious control

Terminology

• Postural control: the ability to control the body’s position in space for the dual purposes of orientation and stability

1) Orientation: the ability to maintain appropriate task-specific relationships between the body segments and between the body and the environment

2) Stability: the ability to control the center of mass relative to the base of support

3 components of postural control mechanism

- Normal postural tone

- Reciprocal innervations

- Common movement pattern (learned pattern)

Human movement – postural tone

• Postural tone generated by changes in the

location of the head

- move on the same axis against the BOS

- activate the neural system of the brain

Human movement – reciprocal innervations

• Reciprocal innervations

- Agonist, antagonist, synergist

- Proximal stability, distal mobility

Human movement- common movement pattern

• Previous information, current information

• Adaptive, anticipatory

Postural tone

• In daily life, human keep working against

gravity to maintain the head in the axis

• Postural tone starts to work from the moment

the head in space

Terminology

• Tone : resistance of muscle to stretch

phasic and postural

• Phasic tone – rapid contraction in response to a high- intensity

stretch, as in tendon reflex response

• Postural tone – prolonged contraction of antigravity muscles in

response to the low-intensity stretch of gravity. When postural

tone is depressed, the trunk and limbs cannot maintain

themselves against gravity

Postural tone

• An appropriate activation of muscle of the

body to maintain the head & body on midline

against gravity

• Information tools which are the vestibular

network of eye, inner ear, muscle spindles of

the neck and trunk

Mechanisms for modulation of postural tone

• Postural tone automatically works to

allow head movement in space in order

to do something with volition


• Standing

• Soldier – military standing at attention

• Lying down in bed

• Initial wakefulness with opening of eye

• Sitting


• Straightened neck with 2 columns of upper trapezius

The Neck

• Muscles which locate around the neck are most important, which

is the basis for the postural control of human movement

• It works with vestibulospinal reflex, vestibulocollic reflex,

vestibuloocullar reflex

• For connecting with vestibular neural network, neck muscles are

composed of highest density of muscle spindle then other

muscles


• Hemiplegia – muscle weakness, hypertonus SCM, upper

trapezius column weakness or disappearance

• Premature diplegia – low proximal tone

• Weak or shortened neck

-inability to watch with two eyes and to straighten the neck

Basis of neural network for the modulation of postural tone

• Otolith, the utricle and saccule.

- LVN

- ipsilaterally extensor m. in the cervical & lower lumbar

segment of spinal cord

• Semicircular canal

- MVN

- bilaterally cervical or upper thoracic of spinal cord

- extensor m. facilitation, flexor m. inhibition

Netter ‘97


• Vestibular nuclei

1. Sensory information about head movement &

head position relative to gravity

2. Gaze stabilization

3. Postural adjustment

4. Autonomic function and consciousness

Model ComponentsSensory Organization

• Balance/postural control via

three systems:

– Somatosensory

– Visual

– Vestibular

Somatosensory System

• Dominant sensory

system

• Provides fast input

• Reports information

– Self-to-(supporting)

surface

– Relation of one

limb/segment to another

• Components

– Muscle spindle

• Muscle length

• Rate of change

– GTOs

• Monitor tension

– Joint receptors

• Mechanoreceptors

– Cutaneous receptors

Vestibular System

• Not under conscious

control

• Assesses movements of

head and body relative to

gravity and the horizon

(with visual system)

• Resolves inter-sensory

system conflicts

• Gaze stabilization

• Components

– Cerebellum

– Projections to:

• Brain stem

• Ear

Sensory-Motor Integration

Somatosensory

Vestibular

Visual

Eye Movements

Postural Movements

10 Processor

20 ProcessorCerebellum

Motoneurons

Sensory Input Processing Motor Response

Normal Postural ControlSensory System

• The somatosensory system provides information

about the body with reference to supporting

surfaces.

• The somatosensory system receives information

from muscle spindles, joint receptors, tendon

organs, and mechanoreceptors.


• Modulation Of Postural Tone

• Higher Position

Basis of neural network for movement of the body

• Standing

• The top is the head which is the keystone of the central line

• Vestibular system contributes to the generation of postural

tone regarding to the location of the head for maintaining

posture and for preparing the body movement


• In sitting: gluteus maximus initiator of respond the change

of head location

• Rest a sofa

- head flexed, body lean backward

• Sacrum sitting

• When intend to do something

- head higher, pelvis upright, gluteus maximus, back m

extension


• The most important consideration is the

adequate & right activation of the head

• Gluteus maximus


• For another instance

- human stand up

• Head flexion, proximal m. flexion

• Pelvis automatically ant. tilting

- leg flexion – for supporting the weight of the head & the

body

Special consideration body parthuman movement

1. Eye with the head

2. Neck dynamic stability

3. Shoulder joint

4. Hand

5. Proximal dynamic stability

6. 3-dimensional pelvic movement

7. Ankle, foot

CERVICAL AND THORACIC

SPINE

HAND MOVEMENT

PROXIMAL DYNAMIC STABILITY

3 – DIMENSIONAL PELVIC MOVEMENT WITHOUT or WITH BOS

THE PELVIS MOVES ONTO THE HIP JOINT

FOOT /ANKLE, TOE AS A BOS

NECK DYNAMIC STABILITY

HEAD / EYE

POSTURAL TONEAXIS

Altered vestibular system

• Eyes

- connecting signals from the vestibular network

- helping modulation of postural tone

• VOR

• Neck collarboration

• Vestibular network of the eye and head

- axis에 대해 몸의 위치변화 감지- 머리의 조절

VESTIBULO-OCCULAR REFLEXES


• Sub- occipital spine (atlas- axis complex)

• Trapezius, SCM

• Deep m.


• Hyperextended and asymmetric posture-typical hypertonic pattern

• Insufficient sensorimotor experience

• Womb

- flexed posture, connective movement

• Neck m. (flexor part)

Altered Vestibular System Spastic Diplegia

• Hyperextended neck and eye

which leads extended body.

• Different head Location

mainly activate special

muscles group of extension

for maintain axis.

The eye

• Hyperextended neck, both eye not stable

- alteration of axis

- lead to change muscle, body alignment

• C1,C2 segment fixed

• Neutralization of altered vestibular system

- therapist correct the altered vestibular system, normal axis,

bring the eyes back to the middle

Altered Vestibular System Extended Child

The neck

• Muscles which locate around the neck are most important, which

is the basis for the postural control of human movement

• It works with vestibulospinal reflex, vestibulocollic reflex,

vestibuloocullar reflex

• For connecting with vestibular neural network, neck muscles are

composed of highest density of muscle spindle then other

muscles

The neck

• Spastic quadriplegia, dystonic athetosis

- Activated mainly extensor group

- Caused by dysfunction of the brain

- Hyperextended neck

- Hyperextended body d/t maintain the body axis

The neck

• Hyperextension inhibit C1-C2 complex movement-

altered vestibular system

Spastic diplegia

- Hyperextended neck

- Short neck,

- Disappearance of the SCM, Upper part of trapezius, C7

The neck

• Cannot function optimally

- lead to shortness of trapezius, deep capital

extensor m.

- Strong axis & information center의 기능을 할

수 없게 됨

The neck

• Head – sense its location & movement

• Neck- rotation, flexion, extension

• Vestibular information을 적절히 할 수가 없음

• C.P에서 postural tone 유지가 불가능하면 움직

일 수 없다

The neck

• Lack of rotation from cervical to thoracic

spine

- Unable scapular movement dissociation

- Unable shoulder joint movement

The neck

• Hemiplegia- low proximal tone

• Less movement on more affected side

• Hypertonus

• Poor body scheme

• Less weight bearing

The weakness of the neck

• Weak neck – proximal m. tone low

• Premature diplegia- insufficient postural tone, vestibular information

• Build up muscle of neck c proximal

• Activate two-eye watching

• Spinal rotation


• Hyperkinetic athetosis

• Fluctuating postural tone

- poor head movement

• Neck brace - move axis


• Hemiplegia

- Asymmetry in posture and movement

• SCM, upper trapezius

- activate weak & inactive m.

- postural tone appropriate and correct axis the

body

Connective movement of cervical, thoracic and lumbar spine

• Cervical spine rotation

- thoracic spine rotation

- lumbar spine rotation

• Vestibular network of CNS

- eye not midline, neck weakness

- low proximal tone

- poor connect movement of the spine

Connective movement of cervical, thoracic and lumbar spine

• Diplegia

- connective movement difficult

• Dissociated movement of the scapular

d/t especially poor neck movement

- because hyperextension or flexion

Power and speed: chin tuck

• Chin goes toward the spine – chin tuck

• Weak neck- power, speed not produce

• Hyperextension inhibit chin tuck

Axis keeper

• Neck, hand, gluteus maximus, ankle, toe

• Most strongest stabilizer – chin tuck

• Facial muscle – masseter

• Hand- pushing, pulling

• Gluteus maximus- sever as posture of extension

Axis keeper

• Landau reaction

- gluteus maximus strongly contract

• Upright sitting- highest head position, pelvic ant. Tilting

• In standing – maintaining axis from top to bottom

Axis keeper

• Ankle, toe - strongly contribute

BOS bipedal stance, dynamic movement

• Head is suddenly displaced or lose correct

head alignment

- running, ballet

Axis keeper

• Head is weak or altered vestibular

system

- all axis keeper will weaken or disappear

Proximal dynamic stability

• Proximal, neck dynamic stability

- Stabilization body for distal part movement

- Stabilization of rib cage

• Start to postural tone upon alertness (eye opening)

• Automatic activation

• Initiation of any kind of movement


• Abdominalis, quadriceps, femoris, gluteals, diaphragm

• Proximal, pelvis conversely

- 3-dimensional pelvic movement

• Neural signal from the CNS

• Neuromuscular junction

• Enough number of muscle fiber

• Thus, activation and building up proximal m. are very

important


• 3-dimensional pelvic movement

- Forward, backward, diagonal

• Crawl – one leg flexion, other leg extension

• Greater flexion – opposite greater extension


• If weak- not generate postural tone

• Inactive trunk, muscle tone extensor

• Neck proximal stability – distal part move

• Rib cage & pelvis – arm, leg appropriate movement

• Proximal – neck, pelvis, core muscle

Physiologic postural reflex response

• Head righting reaction

- 출생직후 출현

- 지면에 엎드려 눕히면 고개를 들어올리는 반응

- Landau 와 derotative righting reaction으로 통합

• Landau reaction

- 엎드린 상태에서 영아의 배를 손으로 받치고 들어올림.

- Neck extension, trunk extension


• Derotative righting reaction

1) Head on body righting reaction

- 머리를 한쪽으로 돌리면 어깨, 몸통, 골반, 다리가 그 방향

으로 돌아감.

2) Body on body righting reaction

- 다리를 한쪽으로 꼬아 옆으로 돌리면 골반, 몸통, 어깨관절,

상지 순으로 꼬인 몸을 푼다.

• Optical righting reaction

- 몸을 한쪽으로 기울였을 때, 고개를 똑바로 위치하려고 하는

반응


• Labyrinthine righting reaction

- 눈을 가리고 몸을 한쪽으로 기울이면 전정기관

의 수용체가 자극

→ 목 주위 귺육의 귺 긴장도가 변함.

→ 고개를 똑바로 정위 자세로 위치


• Equilibrium reaction (평형 반응)

- 무게 중심이 몸의 중심에서 벗어났을 때 몸의 중심의 안정성을 다시 확보

ex) 앉은 자세에서 팔을 뻗어 물건을 잡으려 할 때

- Sitting, standing

• Protective reaction

- 무게중심의 이동이 너무 빠르고, 너무 커서 무게 중심을 유지하여 안정성

을 회복할 수 없을 때

ex) Parachute reaction

Thank You for Your Attention.

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